This study investigated the potential of using recycled manhole cover flour (CMC) and medium density fibreboard (MDF) sawdust as low cost fillers for recycled polypropylene (PP) composites. Various compositions of CMC and MDF flour, up to 40 wt% (20 wt% CMC and 20 wt% MDF), were compounded with recycled PP using maleic anhydride grafted PP. The results showed that increasing the filler content improved the bending strength and modulus, reaching 46.4 MPa and 3399 MPa, respectively, at 40 wt% loading. However, the tensile strength decreased slightly with the addition of 10 wt% filler and showed a slight decrease with the increase in filler content from 20 to 40 wt%. The water absorption of the composites showed only a slight increase from 0% for pure PP to 0.007% for composites with 40 wt% filler. Thermogravimetric analysis confirmed the thermal stability of the composites up to about 400°C. This study demonstrated the potential of using a blend of waste CMC and MDF flour up to 40 wt% to improve the strength and water resistance of recycled PP composites, offering a promising and sustainable approach to cost-effective composite production.

中文翻译：

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利用废弃井盖和纤维板作为热塑性复合材料的增强填料

本研究调查了使用回收的井盖粉 (CMC) 和中密度纤维板 (MDF) 锯末作为回收聚丙烯 (PP) 复合材料的低成本填料的潜力。使用马来酸酐接枝 PP 将高达 40 wt%（20 wt% CMC 和 20 wt% MDF）的各种成分的 CMC 和 MDF 面粉与回收的 PP 进行复合。结果表明，增加填料含量可提高弯曲强度和模量，在 40 wt% 负载量下分别达到 46.4 MPa 和 3399 MPa。然而，随着填料含量为 10 wt%，拉伸强度略有下降，并且随着填料含量从 20 wt% 增加到 40 wt%，拉伸强度也略有下降。复合材料的吸水率仅略有增加，从纯 PP 的 0% 到含有 40 wt% 填料的复合材料的 0.007%。热重分析证实了复合材料在高达约 400°C 的温度下具有热稳定性。这项研究证明了使用高达 40 wt% 的废 CMC 和 MDF 面粉混合物来提高回收 PP 复合材料的强度和耐水性的潜力，为经济高效的复合材料生产提供了一种有前途且可持续的方法。